RDMA/efa: Support remote read access in MR registration

Enable remote read access for memory regions in order to support RDMA
operations.

Link: https://lore.kernel.org/r/20191121141509.59297-3-galpress@amazon.comSigned-off-by: NDaniel Kranzdorf <dkkranzd@amazon.com>
Reviewed-by: NYossi Leybovich <sleybo@amazon.com>
Signed-off-by: NGal Pressman <galpress@amazon.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/efa/efa_admin_cmds_defs.h

@@ -362,9 +362,13 @@ struct efa_admin_reg_mr_cmd {
 
 	/*
 	 * permissions
-	 * 0 : local_write_enable - Write permissions: value
-	 *    of 1 needed for RQ buffers and for RDMA write
-	 * 7:1 : reserved1 - remote access flags, etc
+	 * 0 : local_write_enable - Local write permissions:
+	 *    must be set for RQ buffers and buffers posted for
+	 *    RDMA Read requests
+	 * 1 : reserved1 - MBZ
+	 * 2 : remote_read_enable - Remote read permissions:
+	 *    must be set to enable RDMA read from the region
+	 * 7:3 : reserved2 - MBZ
 	 */
 	u8 permissions;
 
@@ -780,6 +784,8 @@ struct efa_admin_mmio_req_read_less_resp {
 #define EFA_ADMIN_REG_MR_CMD_MEM_ADDR_PHY_MODE_EN_SHIFT     7
 #define EFA_ADMIN_REG_MR_CMD_MEM_ADDR_PHY_MODE_EN_MASK      BIT(7)
 #define EFA_ADMIN_REG_MR_CMD_LOCAL_WRITE_ENABLE_MASK        BIT(0)
+#define EFA_ADMIN_REG_MR_CMD_REMOTE_READ_ENABLE_SHIFT       2
+#define EFA_ADMIN_REG_MR_CMD_REMOTE_READ_ENABLE_MASK        BIT(2)
 
 /* create_cq_cmd */
 #define EFA_ADMIN_CREATE_CQ_CMD_INTERRUPT_MODE_ENABLED_SHIFT 5

drivers/infiniband/hw/efa/efa_com_cmd.c

@@ -230,8 +230,7 @@ int efa_com_register_mr(struct efa_com_dev *edev,
 	mr_cmd.flags |= params->page_shift &
 		EFA_ADMIN_REG_MR_CMD_PHYS_PAGE_SIZE_SHIFT_MASK;
 	mr_cmd.iova = params->iova;
-	mr_cmd.permissions |= params->permissions &
-			      EFA_ADMIN_REG_MR_CMD_LOCAL_WRITE_ENABLE_MASK;
+	mr_cmd.permissions = params->permissions;
 
 	if (params->inline_pbl) {
 		memcpy(mr_cmd.pbl.inline_pbl_array,

drivers/infiniband/hw/efa/efa_com_cmd.h

@@ -178,12 +178,7 @@ struct efa_com_reg_mr_params {
 	 * address mapping
 	 */
 	u8 page_shift;
-	/*
-	 * permissions
-	 * 0: local_write_enable - Write permissions: value of 1 needed
-	 * for RQ buffers and for RDMA write:1: reserved1 - remote
-	 * access flags, etc
-	 */
+	/* see permissions field of struct efa_admin_reg_mr_cmd */
 	u8 permissions;
 	u8 inline_pbl;
 	u8 indirect;

drivers/infiniband/hw/efa/efa_verbs.c

@@ -70,7 +70,8 @@ static const char *const efa_stats_names[] = {
 #define EFA_CHUNK_USED_SIZE \
 	((EFA_PTRS_PER_CHUNK * EFA_CHUNK_PAYLOAD_PTR_SIZE) + EFA_CHUNK_PTR_SIZE)
 
-#define EFA_SUPPORTED_ACCESS_FLAGS IB_ACCESS_LOCAL_WRITE
+#define EFA_SUPPORTED_ACCESS_FLAGS \
+	(IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_READ)
 
 struct pbl_chunk {
 	dma_addr_t dma_addr;
@@ -1382,7 +1383,7 @@ struct ib_mr *efa_reg_mr(struct ib_pd *ibpd, u64 start, u64 length,
 	params.pd = to_epd(ibpd)->pdn;
 	params.iova = virt_addr;
 	params.mr_length_in_bytes = length;
-	params.permissions = access_flags & 0x1;
+	params.permissions = access_flags;
 
 	pg_sz = ib_umem_find_best_pgsz(mr->umem,
 				       dev->dev_attr.page_size_cap,